1. Field of the Invention
The present invention relates to a clock-synchronous semiconductor memory device and access method thereof which operates synchronously with a basic clock signal, and, in particular, to a clock-synchronous semiconductor memory device and access method thereof in which an address for accessing can be set synchronously with a basic clock signal, and a clock-synchronous semiconductor memory device and access method thereof in which an address for accessing can be set when a high-frequency basic clock signal is used.
2. Description of the Prior Art
The inventors of the present invention have previously proposed a basic method for controlling a memory operation for a semiconductor memory device synchronized with a basic clock signal (Japan Application No. 3-255354).
At that time, several methods were illustrated for controlling a memory access by means of an external control signal, but nothing was disclosed how to set a external control signals synchronously with a basic clock signal and with respect to setting specific timing for an address signal or the like for the external control signals.
Moreover, there is a problem that it is difficult to access data when a high-frequency basic clock signal is used in a conventional a clock-synchronous semiconductor memory device and access method thereof.
According to an aspect of the present invention, there is provided a semiconductor device comprising a memory cell array having memory cells arranged in rows and columns, the memory cells storing data and being selected according to address signals; control section configured to receive a clock signal and a first control signal, and configured to output a plurality of the data in synchronism with the clock signal after the first control signal is asserted, output of the data beginning a number of clock cycles (latency N) of the clock signal (latency N being a positive integer xe2x89xa72) after the first control signal is asserted, a different one of the data being output at each of the clock cycles after the output begins until the plurality of data is output, and a latency setting circuit configured to set the latency N, the latency setting circuit including at least one switch which permanently fixes a latency.